Addison Disease (Adrenal Insufficiency)

Chronic adrenal failure—usually autoimmune.

Features: fatigue, a/n/v, diarrhoea, abdominal pain, weight loss, dizziness, postural hypotension, hyperpigmentation (mouth, hard palate, skin creases of palm).

Investigations: K⁺ ↑, Na⁺ ↓, glucose ↓, cortisol ↓, short synacthen stimulation test (key test); adrenal autoantibodies.

Note: notorious for delayed diagnosis with possible wasting, death and Addisonian crisis provoked by stress, e.g. infection, surgery. Requires urgent resuscitation with IV fluids and hydrocortisone.